In various wireless communications and radar systems, information transmitting and receiving both depend on antennas. With the rapid development of large-capacity, multifunctional, and ultra-wideband integrated information systems, a quantity of information carried on a same platform greatly increases, and a quantity of required antennas also increases correspondingly. This is contradictory to the trend of development that requires the antenna to reduce total costs of the integrated information system, reduce a weight, reduce a scattering cross-section of radar on the platform, implement a good electromagnetic compatibility feature, and the like. The emergence of a multi-polarization antenna can effectively resolve this contradiction, and the multi-polarization antenna can dynamically change a working polarization mode of the multi-polarization antenna according to a requirement of an actual application, so as to provide a polarization diversity to resolve multi-path fading and increase a channel capacity.
An existing directional coupled feeding low-profile back cavity round polarization antenna (patent CN200710156825.2) needs to use a microstrip to feed electricity due to a circuit structure and a size; as a result, feeding efficiency is reduced in a high frequency application.